+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Factors influencing the abundance of Trioxys pallidus, a successful introduced biological control agent of walnut aphid in California



Factors influencing the abundance of Trioxys pallidus, a successful introduced biological control agent of walnut aphid in California



Biological Control 48(1): 22-29



This field study reports on factors influencing the abundance of Trioxys pallidus 35 years after its successful introduction in California, and in the presence of continued hyperparasitism and intraguild predation. The seasonal activity of Chromaphis juglandicola and T. pallidus were monitored in 2005-06 in relation to hyperparasitism and mummy predation in three orchards. Walnut aphids remained under the economic threshold in all three orchards with insecticide treatments for other pests in some cases reducing aphid populations as well. No significant density-independent or density-dependent aggregation in the risk of hyperparasitism was found at the individual tree scale, suggesting the absence of a refuge from hyperparasitism. In contrast, significant negative density-dependent aggregation in the risk of intraguild predation was found, but no density-independent aggregation, suggesting a refuge at higher mummy densities. Using a linear mixed effects model, the following factors were found to influence mummy density: aphid density from the previous sample date and intraguild predation, with the latter linked to hyperparasitism from the previous sample date through a significant interaction that appears to be mediated by current aphid density.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 037421384

Download citation: RISBibTeXText

DOI: 10.1016/j.biocontrol.2008.09.014


Related references

Biological control of the walnut aphid in california usa impact of the parasite trioxys pallidus. Hilgardia 47(1): 1-14, 1979

Biological control of the walnut aphid in California: impact of the parasite, Trioxys pallidus. Hilgardia 471: 1-13, 1979

Initial field observations in California on Trioxys pallidus (Haliday) a recently introduced parasite of the Walnut aphid. J. econ. Ent, 55: 6, 857-62, 1962

Comparative genetics of invasive populations of walnut aphid, Chromaphis juglandicola , and its introduced parasitoid, Trioxys pallidus , in California. Ecology and Evolution 8(1): 801-811, 2018

The field ecology of the walnut aphid, Chromaphis juglandicola (Homoptera: Aphididae) and its introduced parasite, Trioxys pallidus (Hymenoptera: Aphidiidae): a qualitative and quantitative assessment of population regulation. Dissertation Abstracts International B Sciences and Engineering, 414: 1234, 1980

Trioxys pallidus . . . an effective new walnut aphid parasite from Iran. Calif. Agric, 24: 11, 8-10, 1970

Population changes of Trioxys pallidus, a parasitoid of walnut aphid in Qazvin province. Iranian Journal of Forest and Range Protection Research 3(1): 23-30, 98, 2005

Monitoring laboratory and field biotypes of the walnut aphid parasite, Trioxys pallidus, in population cages using RAPD-PCR. Biocontrol science and technology(3): 313-327, 1995

Toxicity of benzoylphenylureas and thuringiensin to trioxys pallidus hymenoptera braconidae and the walnut aphid chromaphis juglandicola homoptera aphididae. Journal of Economic Entomology 78(5): 1133-1137, 1985

Discriminating between biotypes of the walnut aphid parasite, Trioxys pallidus (Hymenoptera Aphidiidae), using random amplified polymorphic DNA (RAPD) markers. 1994

Release, dispersal, and recovery of a laboratory-selected strain of the walnut aphid parasite Trioxys pallidus (Hymenoptera: Aphidiidae) resistant to azinphosmethyl. Journal of Economic Entomology 83(1): 89-96, 1990

A comparative study on the fecundity, developmental time and adult longevity of walnut aphid, Chromaphis juglandicola (Kalt.), and its parasitoid wasp, Trioxys pallidus (Hal.). Journal of Science and Technology of Agriculture and Natural Resources 6(3): 241-254, 2002

Biological control of the walnut aphid in California: the interrelationship of the aphid and its parasite. Environmental Entomology 2(4): 561-568, 1973

Biological control of walnut aphid in California the interrelationship of the aphid and its parasite. Environmental Ent 24: 561-568, 1973

Biological control of the walnut aphid in California; the interrelationship of the aphid and its parasite. Environmental Entomology 2(4): 561-568, 1972